1. Field of the Invention
The present invention relates to an address setting method which can be used in a communication system constructed by connecting a plurality of ring type networks mutually via a plurality of relay stations in a data exchangeable manner and also can set their own addresses to the plurality of relay stations respectively to enable mutual discrimination of their identity. More particularly, the present invention relates to an address setting method capable of setting their own addresses to a plurality of relay stations respectively based on simple process procedures and also improving throughput as a whole communication system in setting the addresses, and a communication system to which the address setting method is applied.
2. Description of the Prior Art
In the prior art, as disclosed in Patent Application Publication (KOKAI) Sho 59-62245, for example, the communication system has been commonly known in which a plurality of local area networks (abbreviated as "LANs" hereinafter) for carrying out data exchange between a plurality of communication stations are connected via a plurality of relay stations such as gate ways to enable data exchange between different LANs.
In the communication system in the prior art, upon carrying out data exchange between different LANs, addresses to enable mutual discrimination of their own identity must be allocated previously to a plurality of relay stations respectively.
Therefore, in the prior art, as disclosed in Patent Application Publication (KOKAI) Hei 4-326896, for example, the address setting method used in the communication system in which at least one master apparatus and a plurality of slave apparatuses are connected on the same communication bus has been publicly known.
In the communication system disclosed in the above Publication, each of the plurality of slave apparatuses comprises a storing means for storing its own communication address updatably and a connection requesting means for transmitting its own connection requesting information to the master apparatus upon starting the communication system, while at least one master apparatus comprises a communication address setting means for setting the communication address of the slave apparatus as the source of such connection requesting information to another address being different from other slave apparatuses mutually and then informing the concerned slave apparatus of such set communication address when it receives the above connection requesting information.
According to the above communication system, the connection requesting means in each slave apparatus can transmit its own connection requesting information to the master apparatus at the time of starting the communication system while, when the communication address setting means in the master apparatus receives the above connection requesting information from each slave apparatus, it can set the communication address of the slave apparatus as the source of such connection requesting information to another address being different from other slave apparatuses mutually and then informing the concerned slave apparatus of the set communication address. Hence, even though a plurality of slave apparatuses are connected on the same communication bus, the address to enable mutual. discrimination of their identity can be set firmly to each slave apparatus.
However, according to the address setting method in the above communication system in the prior art, the master apparatus, when receiving the connection requesting information from respective slave apparatuses, has allocated/set the communication address of the slave apparatus as the source of such connection requesting information to be different from addresses of remaining slave apparatuses mutually and then returned/informed the set communication address to/of the concerned slave apparatus individually. Hence, the address settingmethod in the prior art has such a problem to be overcome that process procedures for exchanging data including the connection requesting information, the communication address, etc. between the master apparatus and the plurality of slave apparatuses individually are complicated.
In addition, a total sum of time consumed to carry out data exchange individually, i.e., a time required for address setting has tended to become longer. As a result, the address setting method in the prior art has also another problem to be overcome that it is difficult to improve throughput as a whole communication system in setting addresses.